Method and apparatus for producing cellulose.



A. MITNTZING.

METHOD AND APPARATUS FOR PRODUCING CELLULOSE.

APPLIGATION FILED JULY 10,1906

In w: R602" PATENTED MAR. 24, 1908.

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ALVAR MUN'JZING, or S'TOUlrIHOLM, SWEDEN.

METHOD AND APPAQRA'IlJUEl PRUID'UGIIQ'G CELLULOSE.

To all whom it may coocern: Be it 'lu'iown that l, ALVAR lVlllN'lZlfG, a, subject Olfthe King oi. lilwcdeii, and resident of "Vestro illriirlglzidsgoteu ll, Stockholm. Sweden, have in'vcntell it new mid useful improvement in Methods of and Apparatus for Producing (lelluiose, of which the following is a specification, reference being bad to the drawing uccouipii 11g and lorinii'ig u port heir-Jot.

This irureritiou relqtes to improvements in methods cl and. my gorotus for producing Jo by digestlr r wood. or the hire,

all methods hi, icrto employed for di cellulose by coohingor boilim the lttW material, tor instuuee Wood cut to fec s, been.

1 led in iliuesters oi VttliOUS ructious. tlommozi to all those inctlr it: that the cooking; or boiling oi the wood with tho coohiugz; lye for freeing; the fibers of cellulose, l y" more or less solvioglo- :iiul other muttcrs at i, iii the row iiiozteriul to the fiber oi the cellulose, perloruied with tho same dose, uritil tho digusting considered to be finished. in so doing; the cbemici ls employed for preparing the boiling lye, such as caustic olhulies,

' cuustic aillrelies in combination with suliuret of soda or sulfur-cl, of potassium, acid sulfuro'us salts, ctc, in continued action .upori the fiber of cell'ulose'will not also upon the latter, so to weaken and also more or less to dis-- solve it. Especially with high temperature and great pressure, it was not possible to reyent at least part of the fibers of cellulose lrom being weiihcncd and other parts from being); dissolved, this suiting in neither so lame amount nor of so good it quality oi pulp EJLS possible. To this C(H'ltl'llHltQr-l, as for Wood is'conceuucil, thut parts thereof. 21H, lOOl 11" more ccsily digested than other ports simultuiieously proseol in the lioilor. 'i-oi', the Supply ol lyo must be so l r emill tho boiling contiuuod for so 1 mid decomposing also ol the lnznl boilml wood or other raw omloriol; it cannot thou ed that tho loose coil vosilyhoilod ow l coiituiiioll iu' llu boilor will be, so lo muteria,

cc, sonic or if" il'wrsfwill ho \wulwoml orlololly my ol'lru urls ol' the Wood to too luilil lioilmi, in consouoonro ol' which Specification of Lettom FEo'tent.

Application filed. July 10, 19-96.

x'fi time as to secure it sulhcloot dissmv- Patented March 24, 1908 lerl ul No. 3255550.

i disadvantages will for this reason be met with.

The boiling methods hitherto used have further the disadvantage that the boiling lye has the greatest strength and effectiveness when being filled iii and at the beginning of the boiling. As at consequence, the acting chemicals Will attack with their greatest energy the fibers of Wood first met With and, on account the impossibility of a perfect dis tribution of the boiling lye among oi Wobd tellingolece 1110116 moment, some fibers of Wood will be more strongl Y attacked their other therefore be W6L coed and portly dissolved.

The object oi the present invention is a method ol and uppurctus for producing cel lulose by the process ol' boilino wood or the llliQ, in. which the said disadvantages are l5"Ol.(l.t-;Ll. I I

The invention consists, briefly, in effecting powerful cireulctiou oi the boiling lye, suit ebly in such o, muuuer as to couse the lye to run oil in a, continuous stream from the digestcr and thus withdruw the disengaged libe' ol cellulose. This boiling lye, that is led through sulliciently large tubes, is driven through any suitable strainers, for instance so-czillcd filter presses such as are used in niouul'octuring sugar, china-clay etc., but espcciully adapted for the purpose in question. The fibers in said stroioers, While the escaping lye is forced by moons of any suitable pumping arrungemont into the other end or side of the boiler, thus in such it manncr as to pass through the mass that is beingdigestod.

lo the accompanying drawing Figure 1 shows schoimilicully an arrangement of the zqrpumtus uccordiug to this invention when using :11 horizontal (ligcstcr, and Fig. 2 u similar orrongomout, when using an upright ligosh-1n llch-rriug to the drawing, A is the horizontul boiler, which by the rolling tires B rests in suitoblo wheels, and is adopted to be rotated by mucus of any suitable transmission (luViWB.

, l is the lid oi o momhole for introducing the pulp-wood.

the fibers i O is a pumping arrangement by which the lye issuing from F is brought back to the boiler either directly or through a heating apparatus H. When required, new boiling lye can be supplied through the tube K. During the boiling and circulation of the lye the boiler is rotated with a suitable rapidity for causing the raw material of cellulose contained in the boiler to separate, by rubbing, the (fiber of cellulose, according as it becomes rea y.

The arrangement shown in Fig. 2 differs from that illustrated in Fig. 1 only therein that the lye escapes from the lower end of the boiler and is brought back to the u per end thereof. In this arrangement the 'oiler remains stationary during the circulation but, if desired, it may be provided with an arrangement for transmission of movement, so that the boiler may at times be rotated about a horizontal shaft J, in which case the lye conduits obviously ought to be disjoined and the boiler closed by cocks or taps.

The lye that remains in the fiber of cellulose detached in the apparatus therefor employed (filter press or the like) should be washed away in any suitable manner and purified for recovering the chemicals used for the lye, when alkali in any form is used in the boiling operation. Instead of the quantity of lye thus removed during the boiling new lye of suitable strength should be successively added, whereby it will be possible to keep the boiling lye more uniform in strength during the whole time of boiling than is possible in usual boiling methods. By this invention it not necessary at the commencenwnt of the boiling or after new charge of wood supply to have stronger lye than it ordinarily need to be in order to detach the fiber.

In case the fiber can be (,letachedand sulliciently cleaned without the use of pressure the su ply of new raw material can be successive y performed during the progress of the boiling, in which case the boiler is kept stationary during the time the charging takes place. When steam pressure is required, two boilers may be used alternately, one being cleaned and charged while the other is working. When the boiling has proceeded so long that a new supply is required, the boiling lye is removed from the latter boiler to that one that is being charged.

By thepresent method the great advantage, which constitutes an essential object of the invention, is gained that the )ulp-wood does not need to be cut to pieces, but blocks or ribs of wood can be placed in the boiler in any convenient lengths. The expenses for cutting the wood into pieces thereby saved, and the considerable loss of wood also spoiled in cutting is avoided, besides no [ibers are shortened by cutting.

When using a horizontal boilcl' and undivided blocks or ribs of pulp wood placed horizontally in the boiler, the latter may be rotated so fast that the fiber of cellulose is rubbed away from the surfaces of the block or rib as soon as it is digested, which obviates the disadvantages of the old method as set forth in the first part of this specification.

Another advantage of the present method is that the fibers of cellulose need not be exposed to any pernicious influence by the chemicals. As soon as freed they are removed and withdrawn from the dissolving action of the chemicals that else would follow. The output will therefore, be larger, and the fiber stronger, than with the former methods. Hard and loose wood can be boiled simultaneously without inconvenience and without the fibers of the loose wood being spoiled. Wet wood or dry can be used each for itself or together without any inconvenience or loss of fibers. The strength of the lye can be kept approximately constant whereby loss and weakening of the fiber is avoidedv This invention can obviously be used for any kind of raw materials.

Instead ofthe combination of one apparatus of each kind, as shown in the drawing, obviously a plurality of such apparatus can be used. One or more of the apparatus, for instance the strainer may in some cases be dispensed with. Instead of using a separate heater for the lye, steam can be led directly into the boiler, or the boiler be heated in any other suitable manner;

Having now described my invention, I claim:

1. In a process of manufacturing cellulose boiling wood or the like, the steps which consist in causing the lye to flow through the boiler, causing the detached fibers to escape from the boiler with the lye, catching the fibers outside the boiler, and causing the lye to run back to the boiler, substantially as and for the purpose set forth.

2. In a process of manufacturing cellulose by boiling wood or the like, the steps which consist in causing the lye to flow through the boiler, causing the fibers detached within the boiler to escape therefrom with the lye, catching the fibers outside the boiler, causing the lye to run back to the boiler, and adding fresh lye to the inflowing lye before used, substantially and for the purpose set forth.

3. In a process of manufacturing cellulose by boiling wood or the like, the steps which consist in causing the lye to flow through the boiler, causing the fibers detached within the boiler to escape therefrom with the lye, catching the fibers outside the boiler by straining the lyefied forcing the lye freed from the fibers back Into the boiler, substanlially as and for the purpose set forth.

4. In a process ofrnarnifacturing cellulose by boiling wood or the like, the steps which eeweo consist in placing the wood in theboiler in the shape of blocks, causing the lye to flow through the boiler, causing the ilibers deteched' from the blocks within the boiler to esea e therefrom with the outflowing lye, eete ing the fibers outside the boiler, and

foreingthe lye freed from the fibers back 1 into the boiler, substantially as and for the purpose set forth.

5. In an apparatus for manufacturing cellulose by boiling wood or the like, the combination of a boiler, e, conduit connected to the boiler in such a n'i'anner as to allow the lye flowing through the boiler to withdraw therefrom the fibers of cellulose detached during boiling, means for causing the lye to circulate through the boiler and conduit, and a. filtering apparatus inserted in the conduit for retaining the fibers, substentially as and for the purpose set forth. I

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALVAR MUNTZING.

Witnesses:

KARL RUNOSKOG, ELLEN Lovi'm. 

